Technical Abstract:
Selenium (Se) metabolism depends on its chemical form, thus it is probable that different food sources of Se will have unique metabolic fates. The retention and distribution of Se from broccoli and meat were studied in rats (n=8/group) fed: (1) Se-deficient (<0.01 ppm Se) diet, (2) Se-deficient (<0.01 ppm Se) diet, (3) 2ppm Se as high-Se broccoli and (4) 2ppm Se as high-Se meat. Groups 1&3 received 1.5 uCi of 75Se as labeled broccoli and groups 2&4 received 1.5 uCi as labeled meat; rats were killed 2 or 10d later. Whole body 75Se retention was greater from labeled meat than broccoli, but only in animals fed the low-Se diet (p<0.05). On d2, most tissues/organs of animals fed low-Se diets retained 75Se from meat significantly better than 75Se from broccoli, but in animals fed 2 ppm Se only the plasma, kidney and thymus retained 75Se from meat better than from broccoli (p<0.05). By d10, 75Se from meat was still better retained than 75Se in almost all tissues/organs from Se-deficient animals, but there were no significant differences in animals fed 2ppm Se. A second experiment of a similar design used SDS-PAGE followed by phosphor-imaging to track 75Se incorporation into proteins. 75Se from meat was abundant in proteins but little 75Se from broccoli was found. These data demonstrate that the metabolism of Se from a food depends on the specific food consumed as well as the Se status of the animal.